New degrowth paper is way off on electric trucks.
sciencedirect.com/science/articl…
ht @ErikwimDuring
Paper claims eTrucks with range of 800 km need batteries heavier than the allowed weight for truck+load in the EU today.
That's ~10x too much.
Quick takedown thread.
sciencedirect.com/science/articl…
ht @ErikwimDuring
Paper claims eTrucks with range of 800 km need batteries heavier than the allowed weight for truck+load in the EU today.
That's ~10x too much.
Quick takedown thread.
Here's the quote I'm reacting to.
(I've not dissected the rest of the paper.)
Let me calculate for you why this is bollox.
(I've not dissected the rest of the paper.)
Let me calculate for you why this is bollox.
How big is a battery for 800km?
I had a couple of master students study the issue and we concluded that with aero fairings and low rolling resistance tires, the average energy use per km would be close to 1.3 kWh/km.
So 800 km range means around 1 MWh battery.
I had a couple of master students study the issue and we concluded that with aero fairings and low rolling resistance tires, the average energy use per km would be close to 1.3 kWh/km.
So 800 km range means around 1 MWh battery.
Right now, cells are about 260 Wh/kg.
Experts expect 400 Wh/kg in 2025. greencarcongress.com/2020/05/202005…
Add 30% weight for the battery pack =>
~300 Wh/kg =>
0.0003 MWh/kg.
So 1 MWh weights 1/0.0003=3333 kg.
That's >10x less than the paper claims!
Experts expect 400 Wh/kg in 2025. greencarcongress.com/2020/05/202005…
https://twitter.com/elonmusk/status/1298017332904620033?s=20
Add 30% weight for the battery pack =>
~300 Wh/kg =>
0.0003 MWh/kg.
So 1 MWh weights 1/0.0003=3333 kg.
That's >10x less than the paper claims!
The theoretical maximum energy density of lithium air batteries is over 10 kWh/kg: 10x lighter still.
Combine it with a 3x more efficient electric motor and its lighter than gasoline/km.
That's not happening anytime soon but it shows you the 2025 value is far from outlandish.
Combine it with a 3x more efficient electric motor and its lighter than gasoline/km.
That's not happening anytime soon but it shows you the 2025 value is far from outlandish.
As we showed in a recent paper, the drivetrain of an electric vehicle can be about 3000 kg lighter.
That means:
ALMOST NO ADDITIONAL WEIGHT FOR AN ELECTRIC TRUCK IN 2025.
researchgate.net/publication/33…
That means:
ALMOST NO ADDITIONAL WEIGHT FOR AN ELECTRIC TRUCK IN 2025.
researchgate.net/publication/33…
Of course we are not there yet so I'm glad the the EU added an allowance of 2000 kg to zero emission trucks.
By the way: trucks are usually volume constrained (the container is full) and not weight constrained (the container is too heavy) which is why hydrogen has a problem.
By the way: trucks are usually volume constrained (the container is full) and not weight constrained (the container is too heavy) which is why hydrogen has a problem.
Before I wrap up: I agree with the writers that we should limit our resource use and that our amount of travel and how we travel is wasteful.
But I am sick and tired of degrowth proponents that bend the facts in order for their dogma to become truth. That doesn't solve anything.
But I am sick and tired of degrowth proponents that bend the facts in order for their dogma to become truth. That doesn't solve anything.
Conclusion: well designed modern low emission heavy eTrucks with 800 km of range are less than 2 tonnes (5%) heavier than diesel equivalents.
They will become LIGHTER around 2025-2030.
Don't let any degrowth proponent using heavily outdated literature tell you otherwise.
They will become LIGHTER around 2025-2030.
Don't let any degrowth proponent using heavily outdated literature tell you otherwise.
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